Process for the extraction of platinum and similar metals from their sands and ores



Fatenteo 5ept. 19, 1322.

RUSSELL THAYER, or rnrriannnrnm, PENNSYLVANIA.

PROCESS FOR EXTRACTION on rna'rINUi/i AND snvrrnan METALS FROM 'rnn'rnv SANDS AND ORES.

1T0 Drawing.

T0 aZZ whom it may concern:

Be it known that 1, Russian. THAYER, a citizen of the United States, and a resident of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Processes for the Extraction of Platinum and vSimilar Metals from Their Sands and Ores, whereof the following is a specification.

invention relates to the extraction of platinum metals e., those of the so-called ilatinum group, which are commonly found in nature associated with platinum), from ores in which these noble metals exist in a finely divided or even colloidal state As an example ofsuch ores may be cited the sands P characteristic of the deposit of Herkimer County, New York.

There is reason to believe that divided metals in both sand and rock ores are, largely, dried, coagulated gels from colloidal aqueous solutions, and that in many cases silica was also present in these solutions. The silica may have been either itself in a state of colloidal fineness and solution,

or in particles, coarser than colloidal, sus pended in the true colloidal solution of metal particles. In some cases, these latter relations may have been wholly or partially reversed, as between silica and metal; and in others, again, all the possible relations probably coexisted.

Whatever be the fact as to previous solution, it certainly appears that, geologically speaking, the metal particles in such sand and rock ores have been coagulated or precipitated upon grains of silica which constitute, or, in aggregate, form the ores,or which, perhaps, in the case of rock ores, exist in the matrix of cementing material that binds together the aggregate of sand grains whereof the rock is principally composed.

In my Patents No. 1,273,202, dated July 23rd, 1918, and Nos. 1,281,878 and 1,281,879, dated October 15th, 1918, and in my applications Serial No. 306774;, filed June 26th,

1919, and Serial No. 353,631 filed contemporaneously herewith, I have described methods for the extraction of the platinum metal values from sands and other ores by volatilization,for I have found that, in their finely divided or colloidal state characteristic of such ores, these metals can be volatilthe volatilization Application filed. January 23, 1920. Serial No. 353,632.

ized at relatively low temperatures,-not withstanding their high melting points and high specific gravities. I have also described (in iny'patents and applications just mentioned), the use of various agents in aid of. according to the principles of my invention. These auxiliary agents in clude, in particular, alkali and alkaline earth metal compounds and halogens or halogenous agents, and especially halogen compounds of the alkaliand alkaline earth metals,--such as calcium chloride, sodium chloride, or

fluorspar, singly or two or more together; and advantageously with addition of potassium or sodium hydroxide as any adjunct. I

' My present invention-relates tothe general volatilization, at relatively low temperature-s,preferably with the aid of auxiliary .agents,but involvesa specific improvement over the methods set forth in my aforesaid patents and applications. I have found that the volatilization opera rocess of extraction of platinum meta-ls by 1 tion can be improved, simplified, and cheap- 7 ened, by employing a blast of superheated steam as the direct volatilizing element and vehicle for the metals. How my invention can be practically carried out and applied will appear from the description hereinafter of the best method at present known to me, while its scope and essence will be indicated in my claim.

The following modes of procedure exemplify a typical instance of the practice of my invention.

. Platiniferous sand or ore is preferably ground very fine, say about 200 mesh, in order to release the metal particles from their envelope. The degree of fineness depends, of course, on the character of the sand, or ore, and since in manycases only slight grinding (or even none at all), may be proper to release the metal particles. To one dry ton (of 2000 lbs.) of this sand, or the like, is preferably added an amount of finely divided sodium chloride, (common salt) preferably equal. to about 8 to 10 per cent'thereof by weight, and the added material is intimately mixed with the body of sand, preferably with admixture of .sufiicient water added as such to moisten the charge throughout. The charge is then heated in a suitable container, fur-.

' or retort, to a temperature preferably nace, I of some 200 to 800 centigrade. A blast on its metallic content, a 

